Gravitational Wave Observations

Gravitational Wave Observations

‘Recoiling’ Black Holes

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Black Holes, Recoils

Mains level : Black holes and gravitation waves

A supermassive black hole, which is estimated to weigh up to 100 billion times the mass of the Sun, is seemingly missing, leaving astronomers perplexed.

Try this PYQ:

Q.Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation?

(a) ‘Higgs boson particles’ were detected.

(b) ‘Gravitational waves’ were detected.

(c) Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.

(d) It enabled scientists to understand ‘singularity’.

The ‘missing’ black hole

  • The black hole is supposed to be located in Abell 2261, an enormous galaxy cluster that is about 2.7 billion light-years away from our planet.
  • So, when we look at a celestial object, we are looking at how it appeared that long ago in the past.
  • At 2.7 billion light-years away, the Abell galaxy is at an overwhelmingly large distance away from us.

What could have happened?

  • Every large galaxy in the universe has a supermassive black hole at its centre, whose mass is millions or billions of times that of the Sun, says NASA.
  • The black hole at the centre of our galaxy– the Milky Way– is called Sagittarius A*, and is 26,000 light-years away from Earth.
  • Scientists have been using data gathered in 1999 and 2004 to look for the centre of the Abell galaxy, but have so far been unable to find its black hole.
  • A reason for this could be that Abell’s black hole has been ejected from the centre of the galaxy.

Recoil of Black Holes

  • When two black holes merge, they release what is known as gravitational waves– invisible ripples travelling at the speed of light, which squeeze and stretch anything in their path.
  • As per the theory of gravitational waves, during such a merger, when the amount of waves generated in one direction is stronger than another, the new big black hole can be sent away from the centre of the galaxy into the opposite direction.
  • This is known as a “recoiling” black hole.
  • So far, though, scientists are yet to find definitive evidence for recoiling black holes and are still to discover whether supermassive black holes can merge and release gravitational waves.
  • As of now, only mergers of significantly smaller black holes have been verified.

Why it is significant?

  • The researchers assert that this may have happened because of the merging of two smaller galaxies to form Abell– a process in which both of their black holes merged to form an even bigger black hole.
  • If this hypothesis turns out to be true, it would mean a major breakthrough in astronomy.

Back2Basics:

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Galaxy NGC 6240

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Merger of Black Holes

Mains level : Black holes and gravitation waves

NASA’s Chandra X-ray Observatory shared the images of Galaxy NGC 6240 that contains two supermassive Black Holes in the process of merging.

From astronomers to general space enthusiasts, black holes are a topic of interest for many. If you’re someone who spends a lot of their time researching facts about this region of space-time or watching videos on the same, then you must check out this news.

Galaxy NGC 6240

  • The black holes, located in Galaxy NGC 6240 are 3,000 light-years apart and they will drift together to form a larger black hole millions of years from now.
  • As per a blog post by the observatory, the merging process began some 30 million years ago
  • The pairs of massive black holes in the process of merging are expected to be the most powerful sources of gravitational waves in the Universe.
  • Seen as the bright ‘dots’ near the centre of this image, the black holes are just 3,000 light-years apart.

About Chandra X-ray Observatory

  • It is a telescope specially designed to detect X-ray emissions from very hot regions of the universe such as exploded stars, clusters of galaxies, and matter around black holes.
  • Orbiting at 139,000 km in space, the telescope was launched aboard the Space Shuttle Columbia during STS-93 by NASA in 1999.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

What is Einstein’s Eclipse?

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Einstein’s Eclipse

Mains level : General Relativity

This newscard is an excerpt from the original article published in the DownToEarth.

Einstein’s Eclipse

  • Albert Einstein’s prediction of the bending of light by the gravity of the Sun, one of the components of his general theory of relativity, can be tested during a solar eclipse.
  • Following an unsuccessful attempt to validate this prediction during the Solar eclipse of June 8, 1918, two expeditions were made to measure positions of stars during this eclipse.
  • The eclipse presented a rare chance to verify one of the essential consequences of general relativity, the bending of light by gravity.
  • Einstein’s theory predicted that rays of light passing near a massive body in space would be visibly bent as they followed the curve in space-time created by the body’s mass.
  • In the case of a ray of light originating from a distant star and passing near the edge of the Sun, Einstein calculated a deflection of about 1.75 arc seconds.

Try this PYQ:

Q.Consider the following phenomena:

  1. Light is affected by gravity.
  2. The Universe is constantly expanding.
  3. Matter warps its surrounding space-time.

Which of the above is/are the predictions of Albert Einstein’s General Theory of Relativity, often discussed in media?

(a) 1 and 2 only

(b) 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

What was studied during the eclipse?

  • Einstein published his theory and predictions in 1915, and in 1919 the British physicist Sir Arthur Eddington took advantage of a total solar eclipse to attempt to detect the shifting images of stars near the limb of the sun.
  • The problem was that during totality the sky does not get perfectly dark, and only a handful of stars were visible near the sun from which to make the measurement.
  • The darkness of an eclipse, though, would allow the astronomers to observe and photograph the field of stars around the Sun.
  • By comparing the photographs with reference images taken at night, it would be possible to measure how much the presence of the Sun had bent the stars’ light.
  • Conveniently, a cluster of bright stars known as the Hyades would appear near the Sun during the eclipse.

Significance

  • After several months of analysis, researchers announced in November that their findings supported the theory of general relativity.
  • Media coverage tended to dwell on the recondite nature of Einstein’s work, emphasizing that there were only a handful of people in the world who could understand it.
  • It could be argued that 1919 was the year when Einstein’s name became a byword for superhuman intellectual ability—making possible the small industry of Einstein-themed merchandise that still exists today.

Back2Basics: General Relativity

  • Einstein’s theory proposes that gravity is not an actual force, but is instead a geometric distortion of space-time not predicted by ordinary Newtonian physics.
  • The more mass you have to produce the gravity in a body, the more distortion you get.
  • This distortion changes the trajectories of objects moving through space, and even the paths of light rays, as they pass close-by the massive body.
  • Even so, this effect is very feeble for an object as massive as our own sun, so it takes enormous care to even detect that it is occurring.
  • General Relativity predicts how much of this bending of light you should see given the mass of the object.
  • Called ‘gravitational lensing’ it has been detected on the cosmological scale as entire clusters of galaxies distort the light from more distant galaxies behind them as this image from the Hubble Space Telescope shows.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

New Shephard Rocket System

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Karman Line, New Sphephard

Mains level : Micro-gravity experimentation

New Shephard, a rocket system meant to take tourists to space successfully completed its seventh test launch.

Note the features of the Karman Line. It is a new terminolgy in our recent space vocab.

What is New Shephard?

  • New Shephard has been named after astronaut Alan Shephard, the first American to go to space, and offers flights to space over 100 km above the Earth and accommodation for payloads.
  • Essentially, it is a rocket system that has been designed to take astronauts and research payloads past the Karman line – the internationally recognised boundary of space.
  • The idea is to provide easier and more cost-effective access to space meant for purposes such as academic research, corporate technology development and entrepreneurial ventures among others.
  • It is built by Amazon founder Jeff Bezos’s Space Company called Blue Origin.
  • In 2018, Blue Origin was one of the ten companies selected by NASA to conduct studies and advance technologies to collect process and use space-based resources for missions to the Moon and Mars.

How does it work?

  • The rocket system consists of two parts, the cabin or capsule and the rocket or the booster.
  • The cabin can accommodate experiments from small mini payloads up to 100 kg.
  • The cabin is designed for six people and sits atop a 60-feet tall rocket and separates from it before crossing the Karman line, after which both vehicles fall back to the Earth.
  • The system is a fully reusable, vertical takeoff and vertical landing space vehicle that accelerates for about 2.5 minutes before the engine cuts off.
  • After separating from the booster, the capsule free falls in space, while the booster performs an autonomously controlled vertical landing back to Earth.
  • The capsule, on the other hand, lands back with the help of parachutes.

Back2Basics: Karman line

  • The Karman line is an attempt to define a boundary between Earth’s atmosphere and outer space.
  • The line is named after Theodore von Kármán (1881–1963), a Hungarian American engineer and physicist, who was active primarily in aeronautics and astronautics.
  • He was the first person to calculate the altitude at which the atmosphere becomes too thin to support aeronautical flight and arrived at 83.6 km (51.9 miles) himself.

Locating the line

  • The Fédération Aéronautique Internationale (FAI) defines Karman Line as the altitude of 100 kilometres (62 miles; 330,000 feet) above Earth’s mean sea level.
  • However, other organizations do not use this definition. There is no international law defining the edge of space, and therefore the limit of national airspace.
  • For instance, the US Air Force and NASA define the limit to be 50 miles (80 km) above sea level.
  • The line is approximately at the turbopause, above which atmospheric gases are not well-mixed.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

What is Raychaudhuri Equation?

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Raychaudhuri Equation

Mains level : Not Much

The Raychaudhuri Equation in General Relativity, derived by Raychaudhuri is in the spotlight after 2020 Physics Nobel was awarded to Penrose for throwing light on Black Holes.

Try this MCQ:

Q.The Raychaudhuri Equation is sometimes seen in news is related to:

Artificial Intelligence/Cloud Computing/Quantum Mechanics/Space Sciences

What is Raychaudhuri Equation?

  • Raychaudhuri (1923–2005) was an Indian physicist, known for his research in general relativity and cosmology.
  • In general relativity, the Raychaudhuri equation is a fundamental result describing the motion of nearby bits of matter.
  • It was discovered independently by the Indian physicist Amal Kumar Raychaudhuri and the Soviet physicist Lev Landau.
  • The equation offers a simple and general validation of our intuitive expectation that gravitation should be a universal attractive force between any two bits of mass-energy in general relativity, as it is in Newton’s theory of gravitation.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Physics Nobel for discoveries about Black Holes

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Black Holes

Mains level : Black holes and gravitation waves

Three scientists won this year’s Nobel Prize in Physics for advancing our understanding of black holes, the all-consuming monsters that lurk in the darkest parts of the universe.

Try this PYQ:

Q.Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation?

(a) ‘Higgs boson particles’ were detected.

(b) ‘Gravitational waves’ were detected.

(c) Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.

(d) It enabled the scientists to understand ‘singularity’.

Who are these laureates?

  • Briton Roger Penrose received half of this year’s prize for the discovery that black hole formation is a robust prediction of the general theory of relativity.
  • German Reinhard Genzel and American Andrea Ghez received the second half of the prize for the discovery of a supermassive compact object at the centre of our galaxy.

What are black holes?

  • A black hole is formed when stars collapse and can be defined as a space in the universe with an escape velocity so strong that even light cannot escape it.
  • Escape velocity is the speed at which an object must travel to override a planet or an object’s gravitational force.
  • For instance, for a spacecraft to leave the surface of the Earth, it needs to be travelling at a speed of about 40,000 km per hour.
  • Since light cannot get out, black holes are invisible and can only be tracked with the help of a space telescope or other special tools.
  • And the reason light cannot escape is mainly that the gravity inside a black hole is very strong as a result of a lot of matter being squeezed into a small space.

Their contributions

  • Penrose has been awarded the prize for the discovery that black hole formation is a robust prediction of the general theory of relativity.
  • Genzel and Ghez have been awarded the prize for the discovery of a supermassive compact object at the centre of our galaxy.
  • Penrose’s work has shown that black holes are a direct consequence of Albert Einstein’s general theory of relativity.
  • Einstein himself did not believe that black holes exist and presented his theory in November 1915, providing a new way to look at and understand the gravity that shapes the universe “at the largest scale”.
  • Penrose used Einstein’s general theory of relativity in order to prove that the process of formation of black holes is a stable one.
  • Genzel and Ghez, on the other hand, have discovered that an invisible and an extremely heavy object governs the stars’ orbit at the centre of the Milky Way.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Black Holes Merger

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Black Holes

Mains level : Black holes merger

Billions of years ago, a collision between two black holes sent gravitational waves rippling through the universe. In 2019, signals from these waves were detected at the gravitational wave observatory LIGO (United States) and the detector Virgo (Italy).

Try this PYQ:

Q.Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation?

(a) ‘Higgs boson particles’ were detected.

(b) ‘Gravitational waves’ were detected.

(c) Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.

(d) It enabled the scientists to understand ‘singularity’.

Why in news?

  • The cause of curiosity is the mass of one of the parent black holes, which defies traditional knowledge of how black holes are formed.

What exactly was detected?

  • It was a signal from a gravitational wave, a relatively new field of discovery.
  • Gravitational waves are invisible ripples that form when a star explodes in a supernova; when two big stars orbit each other; and when two black holes merge.
  • Travelling at the speed of light, gravitational waves squeeze and stretch anything in their path.

Detecting gravitational waves

  • Gravitational waves were proposed by Albert Einstein in his General Theory of Relativity over a century ago.
  • It was only in 2015, however, that the first gravitational wave was actually detected — by LIGO. Since then, there have been a number of subsequent detections of gravitational waves.
  • The signal detected at LIGO and Virgo, as described by the LIGO Collaboration, resembled “about four short wiggles” and lasted less than one-tenth of a second.

Where did it come from?

  • Subsequent analysis suggested that GW190521 had most likely been generated by a merger of two black holes. The signal likely represented the instance that the two merged.
  • It was calculated to have come from roughly 17 billion light-years away, and from a time when the universe was about half its age.

Some questions to verify

  • The findings led to further questions.
  • One of the two merging black holes falls in an “intermediate-mass” range — a misfit that cannot be explained by traditional knowledge of how black holes form.

Why is it unusual?

  • All the black holes observed so far belong to either of two categories.
  • One category ranges between a few solar masses (one solar mass is the mass of our Sun) and tens of solar masses. These are thought to form when massive stars die.
  • The other category is of supermassive black holes. This range from hundreds of thousands, to billions of times that of our sun.
  • According to traditional knowledge, stars that could give birth to black holes between 65 and 120 solar masses do not do so — stars in this range blow themselves apart when they die, without collapsing into a black hole.

Observing for the first time

  • In the merger leading to the GW190521 signal, the larger black hole was of 85 solar masses —well within this unexpected range, known as the pair-instability mass gap.
  • It is the first “intermediate-mass” black hole ever observed. (In fact, the smaller black hole to is borderline, at 66 solar masses.)
  • The two merged to create a new black hole of about 142 solar masses. Energy equivalent to eight solar masses was released in the form of gravitational waves, leading to the strongest ever wave detected by scientists so far.

Possible reasons for its formation

  • The researchers suggest that the 85-solar-mass black hole was not the product of a collapsing star, but was itself the result of a previous merger.
  • Formed by a collision between two black holes, it is likely that the new black hole then merged with the 66-solar-mass black hole — leading to gravitational waves and the signal received by LIGO and Virgo.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

GW190412: The first merger of two black holes with unequal masses

Note4Students

From UPSC perspective, the following things are important :

Prelims level : General Relativity, Black Holes, Black Holes merger

For the first time since it started functioning, the gravitational wave observatories at LIGO scientific collaboration have detected a merger of two unequal-mass black holes.

This newscard contains few basic terms that one must know-

Gravitational waves

General Relativity

Black Holes

GW190412

  • The event, dubbed GW190412, was detected nearly a year ago, and this is almost five years after the first-ever detection of gravitational-wave signals by these powerful detectors.
  • Subsequent analysis of the signal coming from the violent merger showed that it involved two black holes of unequal masses coalescing.
  • One of them was some 30 times the mass of the Sun and the other which had a mass nearly 8 times the solar mass.
  • The actual merger took place at a distance of 2.5 billion light-years away.

Significant feature observed

  • The detected signal’s waveform has special extra features in it when it corresponds to the merger of two unequal-sized black holes as compared with a merger of equal-sized black holes.
  • These features make it possible to infer many more things about the characters such as- a more accurate determination of the distance from the event, the spin or angular momentum of the more massive black hole and the orientation of the whole event with respect to viewers on Earth.
  • While the mass of the black hole bends the space-time close to it, the spin or angular momentum of this inscrutable object drags the nearby space-time, causing it to swirl around, along with it.
  • Hence both these properties are important to estimate.

Confirmed General Relativity

  • An Indian team consisting of researchers verified the consistency of the signal with the prediction of General Relativity.
  • The existence of higher harmonics was itself a prediction of General Relativity.

Must refer for an easy and illustrated understanding of General Relativity-

 

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Gravitational Lensing

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Dark Matter, Gravitational Lensing

Mains level : Gravitational Lensing


  • Using NASA’s James Webb Space Telescope as a sort of time machine, researchers plan to investigate how new stars are born.
  • For this, they will take the help of a natural phenomenon called “gravitational lensing”.

Gravitational Lensing

  • The phenomenon occurs when a huge amount of matter, such as a massive galaxy or cluster of galaxies, creates a gravitational field that distorts and magnifies the light from objects behind it, but in the same line of sight.
  • In effect, these are natural, cosmic telescopes; they are called gravitational lenses.
  • These large celestial objects will magnify the light from distant galaxies that are at or near the peak of star formation.
  • The effect allows researchers to study the details of early galaxies too far away to be seen otherwise with even the most powerful space telescopes.

How it works?

  • Normal lenses such as the ones in a magnifying glass or a pair of spectacles work by bending light rays that pass through them in a process known as refraction, in order to focus the light somewhere (such as in your eye).
  • Gravitational lensing works in an analogous way and is an effect of Einstein’s theory of general relativity – simply put, mass bends light.
  • The gravitational field of a massive object will extend far into space, and cause light rays passing close to that object (and thus through its gravitational field) to be bent and refocused somewhere else.
  • The more massive the object, the stronger its gravitational field and hence the greater the bending of light rays – just like using denser materials to make optical lenses results in a greater amount of refraction.

TEMPLATES Programme

  • The Milky Way today forms the equivalent of one Sun every year, but in the past, that rate was up to 100 times greater.
  • NASA now plans to look billions of years into the past in order to understand how our Sun formed.
  • The programme is called Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation, or TEMPLATES.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Scientists to test land for LIGO

Note4students

Mains Paper 3: Science & Technology | Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology

From UPSC perspective, the following things are important:

Prelims level: LIGO

Mains level: Particulars and importance of the proposed LIGO


News

Testing Suitability of Indian site

  1. The Environment Ministry has allowed scientists to test the suitability of land in Maharashtra’s Hingoli district to host the India wing of the Laser Interferometer Gravitational Wave Observatory (LIGO) project.
  2. The project is piloted by the Department of Atomic Energy (DAE) and Department of Science and Technology (DST) and is expected to be ready by 2025.
  3. This is a key step to establishing the one-of-its-kind astronomical observatory.

What does it include?

  1. The project involves constructing a network of L-shaped arms, each four kilometers long, which can detect even the faintest ripples from cosmic explosions millions of light years away.
  2. The discovery of gravitational waves earned three U.S. scientists the Nobel for physics in 2017. The scientists were closely involved with LIGO.
  3. However the construction of such a large, sensitive device — there are only three of its kind in the world — requires an extremely flat surface.
  4. The LIGO-India consortium, made up of physicists from several institutes, had submitted a proposal to “prospect” 121 hectares of forest land in Dudhala village, Hingoli.
  5. For the LIGO project, it is to check if the land can be made perfectly level at a reasonable cost.
  6. The project is in the process of acquiring necessary land some of it is private and some barren forest land.

Network of detectors

  1. The LIGO project operates three gravitational-wave (GW) detectors.
  2. Two are at Hanford in the State of Washington, north-western USA, and one is at Livingston in Louisiana, south-eastern USA.
  3. The proposed LIGO-India project aims to move one Advanced LIGO detector from Hanford to India.
  4. The LIGO-India project is an international collaboration between the LIGO Laboratory and three lead institutions in the LIGO-India consortium:
  • Institute of Plasma Research, Gandhinagar
  • IUCAA, Pune
  • Raja Ramanna Centre for Advanced Technology, Indore
  1. The LIGO lab would provide the complete design and all the key detector components.
  2. Indian scientists would provide the infrastructure to install the detector and it would be operated jointly by LIGO-India and the LIGO-Lab.

Back2Basics

Gravitational waves

  1. Gravitational waves are distortions or ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe.
  2. These ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself.
  3. Any object with mass that accelerates (which in science means changes position at a variable rate, and includes spinning and orbiting objects) produces gravitational waves, including humans and cars and airplanes etc.
  4. But the gravitational waves made by us here on Earth are much too small to detect
  5. The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself.
  6. The LIGO is a large-scale experiment and observatory to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool.

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

A new LIGO gravitational wave detector to be built in India by 2025

Note4students

Mains Paper 3: Science & Technology | Science and Technology- developments and their applications and effects in everyday life Achievements of Indians in science & technology; indigenization of technology and developing new technology

From UPSC perspective, the following things are important:

Prelims level: Particulars of the LIGO

Mains level: Particulars and importance of the proposed LIGO


News

World’s third LIGO detector

  1. A new gravitational wave detector to measure ripples in the fabric of space and time is set to be built in India by 2025
  2. It will be built in collaboration with universities from across the globe
  3. Project: IndIGO

Particulars of the proposed LIGO

  1. The new Laser Interferometer Gravitational-Wave Observatory (LIGO) detector will add to the two already operational in the US
  2. The location for the new detector in India has been selected, and the acquisition has started
  3. However, the site has not been revealed yet
  4. IndIGO, the Indian Initiative in Gravitational-wave Observations, is an initiative to set up advanced experimental facilities, for a multi-institutional Indian national project in gravitational-wave astronomy
  5. The IndIGO Consortium includes
    (1) Indian Institutes of Technology (IIT),
    (2) Indian Institutes of Science Education and Research (IISER) and
    (3) Delhi University, among others

Importance

  1. A third LIGO detector will help pinpoint the origin of the gravitational waves that are detected in future
  2. The LIGO detectors discovered the first gravitational waves produced by two giant merging blackholes last year
  3. The research won a Nobel Prize in Physics this year

Back2basics

Gravitational Wave Observations

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Simply put: Now confirmed, mergers of neutron stars are factories of heavy chemical elements

Source

Note4students

Mains Paper 3: Science & Technology | Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology

From UPSC perspective, the following things are important:

Prelims level: Laser Interferometer Gravitational-Wave Observatory (LIGO), European Southern Observatory (ESO), constellation Hydra, Kilonova

Mains level: Important findings in space have been one of the favorite areas of UPSC


First direct visual identification of the source of a gravitational wave

  1. European Southern Observatory (ESO) has announced the first direct, visual identification of the source of a gravitational wave
  2. Detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) on August 17
  3. This is the first time that such an event has been seen, rather than detected, and the output of numerous telescopes, terrestrial and in orbit, compared to identify a single source
  4. Radiations were detected in optical/near-infrared wavelengths as the counterpart of a gravitational wave source

Nobel Prize for LIGO scientists

  1. On October 3, LIGO founders Rainer Weiss, Barry C Barish and Kip S Thorne were awarded the Nobel Prize in Physics for detecting gravitational waves in 2015, generated by the collision of two black holes

What led to this finding?

  1. In August this year LIGO, together with the Virgo observatory in Italy, detected waves from the cataclysmic merger of two neutron stars, designated GW170817
  2. Soon after, the Fermi space telescope detected a burst of gamma rays from the same region of space, which is a signature of massive stars in collision
  3. The ESO then organized the astrophysical equivalent of a manhunt, marshaling its own resources and those of allied organizations
  4. Its Vista, VST and La Silla telescopes in Chile, along with the US DECam telescope, located the source of light near the galaxy NEC 4993 in the constellation Hydra
  5. The signal was picked up in Hawaii and over the following weeks, about 70 observatories watched the event unfold when they were on the dark side of the earth
  6. The Hubble Space Telescope tracked it, too

What do the observations tell?

  1. The observations place the electromagnetic source at 130 light years away, which matches with the distance to GW170817
  2. It confirms that when neutron stars collide into a kilonova — a body 1,000 times brighter than the average Nova — it produces a gamma-ray burst and gravitational waves
  3. This enormous exercise has joined the dots between various forms of imaging events and objects in deep space
  4. Also, ESO’s experiment has established a much more important principle — that it is now possible to correlate the findings of instruments looking into the sky in different spectra

Back2Basics

Gravitational waves and kilonova

  1. A gravitational wave is a ripple distorting the fabric of spacetime — literally, the universe itself – created when heavy bodies accelerate rapidly
  2. A kilonova (macronova or r-process supernova) is a type of supernova that occurs when two neutron stars or a neutron star and a black hole merge in a binary system
  3. The kilonova was a phenomenon theoretically predicted 30 years ago and was expected to emit short bursts of gamma rays
  4. Gravitational waves were predicted by general relativity a century ago, and it was surmised that colliding neutron stars would emit them
  5. Both phenomena are now observationally confirmed, and a single event is identified as the source
  6. Such phenomena are believed to have generated and spewed out into the universe metals heavier than iron, including precious metals like gold, silver and platinum

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

First LIGO lab outside U.S. may come up in Maharashtra’s Hingoli

  1. The Laser Interferometer Gravitational-wave Observatory (LIGO) project was earlier given the in-principle approval by the Union Cabinet
  2. Scientists along with industry members will be engaged in the construction of the eight km-long beam tube at ultra-high vacuum on a levelled terrain
  3. Thus, LIGO-India will bring considerable opportunities for Indian scientists in instrumentation and development

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Second breakthrough for LIGO detectors

  1. Context: LIGO scientists have announced of finding second pair of merging black hole
  2. Gravitational wave detectors at Livingston, Louisiana, and Hanford have detected the wave
  3. The detection of this merger required the use of sophisticated noise filtering and mathematical analyses
  4. Earlier: A gravitational wave (GW151226) detected on December 26, 2015 and scientists conclude about the emergence of two black holes
  1. Context: LIGO scientists have announced of finding second pair of merging black hole
  2. Gravitational wave detectors at Livingston, Louisiana, and Hanford have detected the wave
  3. The detection of this merger required the use of sophisticated noise filtering and mathematical analyses
  4. Earlier: A gravitational wave (GW151226) detected on December 26, 2015 and scientists conclude about the emergence of two black holes

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Breakthrough Prize for gravitational waves find

  1. Context: LIGO won prize in fundamental physics for its detection of gravitational waves
  2. LIGO: Laser Interferometer Gravitational-Wave Observatory
  3. K.G. Arun of Chennai Mathematical Institute is among the contributor
  4. He joined LEGO through the INDIGO consortium in 2012
  1. Context: LIGO won prize in fundamental physics for its detection of gravitational waves
  2. LIGO: Laser Interferometer Gravitational-Wave Observatory
  3. K.G. Arun of Chennai Mathematical Institute is among the contributor
  4. He joined LEGO through the INDIGO consortium in 2012

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Cabinet clears LIGO-India gravitational wave observatory

  1. Background: The gravitational waves were detected by the Laser Interferometer Gravitational Wave Observatory (LIGO) — a system of detectors in Washington and Louisiana
  2. Context: LIGO-India project, it is piloted by Department of Atomic Energy (DAE) and Department of Science and Technology (DST)
  3. Project cost: at least Rs. 1,200 crore
  4. Way ahead: bring considerable opportunities in cutting edge technology for Indian industry
  5. Which will be engaged in the construction of an 8-kilometre-long beam-tube at ultra-high vacuum on a levelled terrain
  6. Research institutions in LIGO-India project :
  • Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune
  • DAE organisations: Institute for Plasma Research (IPR), Gandhinagar
  • Raja Ramanna Centre for Advanced Technology (RRCAT), Indore

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Indian gravity wave detector 8 years away

  1. Context: Prime Minister supported idea for a US-based LIGO detector in India but such a project is at least eight years away
  2. Background: Estimated to cost around Rs. 1,200 crore project not running into environmental or State-level hurdles
  3. Relevance: India-LIGO project (INDIGO) will be a replica of the 2 LIGO detectors and many of its components have already been built and are ready to be shipped from the United States
  4. Another Project: The Indian Neutrino Observatory (INO) project — a proposed, underground observatory in Tamil Nadu cleared by the government in 2015
  5. What happened? Stalled for over a year due to protests by activist groups, concerned over its environmental impact
  6. Way ahead:  Third detector will likely improve the chances of spotting gravitational waves

LIGO


  1. Context: Prime Minister supported idea for a US-based LIGO detector in India but such a project is at least eight years away
  2. Background: Estimated to cost around Rs. 1,200 crore project not running into environmental or State-level hurdles
  3. Relevance: India-LIGO project (INDIGO) will be a replica of the 2 LIGO detectors and many of its components have already been built and are ready to be shipped from the United States
  4. Another Project: The Indian Neutrino Observatory (INO) project — a proposed, underground observatory in Tamil Nadu cleared by the government in 2015
  5. What happened? Stalled for over a year due to protests by activist groups, concerned over its environmental impact
  6. Way ahead:  Third detector will likely improve the chances of spotting gravitational waves

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Gravitational wave astronomy’s finest moment

  1. Context: The detection of gravitational waves by the scientific community
  2. Indian Contribution: Inter-University for Astronomy and Astrophysics, Pune and the Raman Research Institute (RRI), Bangalore contributed in the analysis of the LIGO data
  3. Importance: The discovery would enable astrophysicists to see the universe, which is invisible to them because about 95% of the universe is known to consist of dark matter
  4. Newtonian gravity theory would be overthrown in favour of Einstein’s gravity by this discovery
  1. Context: The detection of gravitational waves by the scientific community
  2. Indian Contribution: Inter-University for Astronomy and Astrophysics, Pune and the Raman Research Institute (RRI), Bangalore contributed in the analysis of the LIGO data
  3. Importance: The discovery would enable astrophysicists to see the universe, which is invisible to them because about 95% of the universe is known to consist of dark matter
  4. Newtonian gravity theory would be overthrown in favour of Einstein’s gravity by this discovery

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Learn about Gravitational waves

  1. Gravitational waves are distortions in the space-time geometry that propagate with the speed of light, analogous to ripples on the surface of a pond
  2. Current Status: There is indirect evidence for the existence of gravitational waves from the observation of binary pulsars
  3. Research: To detect gravitational waves directly
  4. The worldwide network of gravitational wave detectors had started search for these ripples in spacetime
  1. Gravitational waves are distortions in the space-time geometry that propagate with the speed of light, analogous to ripples on the surface of a pond
  2. Current Status: There is indirect evidence for the existence of gravitational waves from the observation of binary pulsars
  3. Research: To detect gravitational waves directly
  4. The worldwide network of gravitational wave detectors had started search for these ripples in spacetime

By Root

Caretaker @civilsdaily

Gravitational Wave Observations

Important discovery on gravitational waves on cards

  1. Context: Indian researchers are part of the international commitment to detect gravitational waves.
  2. Historical Background: Albert Einstein predicted the existence of gravitational waves in 1915
  3. Consortium: Scientists are working with IndIGO (Indian Initiative in Gravitational-wave Observations) Consortium
  4. Organisation Involved: Inter-University Centre for Astronomy and Astrophysics-Pune
  5. How?- Using Laser Interferometer Gravitational-wave Observatory
  1. Context: Indian researchers are part of the international commitment to detect gravitational waves
  2. Historical Background: Albert Einstein predicted the existence of gravitational waves in 1915
  3. Consortium: Scientists are working with IndIGO (Indian Initiative in Gravitational-wave Observations) Consortium
  4. Organisation Involved: Inter-University Centre for Astronomy and Astrophysics-Pune
  5. How? Using Laser Interferometer Gravitational-wave Observatory

By Root

Caretaker @civilsdaily

Eureka moment: Gravitational waves found

 

Recently, Gravitational waves, the cosmic ripples that distort space-time itself, have been directly detected for the first time. Let’s know about this unprecedented discovery!

What is so special about this eureka moment?

  • For the first time, scientists have observed ripples in the fabric of space-time called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe
  • This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos
  • Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole
  • This collision of two black holes had been predicted but never observed

Let’s first know about Albert Einstein’s general theory of relativity?

  • In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity
  • It introduced a new framework for all of physics and proposed new concepts of space and time
  • Einstein then spent 10 years trying to include acceleration in the theory and published his theory of general relativity in 1915
  • In it, he determined that massive objects cause a distortion in space-time, which is felt as gravity

[ Einstein’s mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source ]

What are Gravitational waves?

Cataclysmic events, such as this artist's rendition of a binary-star merger, are believed to create gravitational waves that cause ripples in space-time
Cataclysmic events, such as this artist’s rendition of a binary-star merger, are believed to create gravitational waves that cause ripples in space-time. Credits: NASA

  • Gravitational waves are distortions or ‘ripples’ in the fabric of space-time caused by some of the most violent and energetic processes in the Universe
  • These ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as invaluable clues to the nature of gravity itself

What are the Sources of Gravitational Waves?

  • Any object with mass that accelerates (which in science means changes position at a variable rate, and includes spinning and orbiting objects) produces gravitational waves, including humans and cars and airplanes etc.
  • But the gravitational waves made by us here on Earth are much too small to detect
  • The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and the remnants of gravitational radiation created by the birth of the Universe itself

InfographLigo-gravitational-waves


Not one but four types of Gravitational Waves!

  • In order to understand the types of gravitational waves, Laser Interferometer Gravitational Wave Observatory (LIGO) scientists have defined 4 categories of gravitational waves
  • These categories are: Continuous Gravitational Waves, Compact Binary Inspiral Gravitational Waves, Stochastic Gravitational Waves, and Burst Gravitational Waves

But, Why Detect Them?

  • This will open up a new window of study on the Universe, giving us a deeper understanding of these cataclysmic events, and usher in brand new cutting-edge studies in physics, astronomy, and astrophysics
  • More importantly, since gravitational waves don’t interact with matter (unlike electromagnetic radiation), they travel through the Universe completely unimpeded giving us a crystal clear view of the gravitational wave
  • This will provide astronomers and other scientists, first glimpses of previously unseen and unseeable wonders, and greatly adding to our understanding of the nature of space and time itself

So, How does LIGO come into the Picture?

  • LIGO( Laser Interferometer Gravitational Wave Observatory) is the world’s largest gravitational wave observatory and a cutting edge physics experiment
  • LIGO exploits the physical properties of light and of space itself to detect and understand the origins of gravitational waves
  • LIGO has 2 widely separated identical detector sites working in unison as a single “observatory”: one in Hanford, southeastern Washington State and the other in rural Livingston, Louisiana
  • LIGO has a very close collaboration with the VIRGO collaboration that analyzes data from VIRGO, a 3 km gravitational wave interferometer located near Pisa, Italy
  • Data from LIGO and Virgo are combined and analyzed together by the LIGO and Virgo collaborations
  • Thus significantly increasing the capability of combined data for detecting and using gravitational waves to learn about nature

Is there any Way ahead for India?

Image - Locations of existing gravitational-wave detectors, and how far out a LIGO in India would be Source: LIGO
Image – Locations of existing gravitational-wave detectors, and how far out a LIGO in India would be. Source: LIGO

  • Yes, because Union cabinet has approved a proposal to establish a state-of-the-art gravitational wave observatory in India in collaboration with LIGO in the US
  • The project will bring unprecedented opportunities for scientists and engineers to dig deeper into the realm of gravitational wave and take global leadership in this new astronomical frontier
  • This will also bring considerable opportunities in cutting-edge technology for the Indian industry which will be engaged in the construction of the 8-km long beam tube at ultra-high vacuum on a leveled terrain
  • With its establishment, India will join the global network of gravitational wave detectors
  • The establishment of an observatory in India assumes importance because the further the distance between the observatories, the greater will be the accuracy in locating gravity waves
  • Maharashtra and Madhya Pradesh are among the states shortlisted for the experiment

Can we expect some answers from you guys?

#Q. Recently, Union cabinet has approved a proposal to establish a gravitational wave observatory, one of the mega science projects in India. Discuss, how will this project help India if it becomes a reality.

 

Published with inputs from Arun | Image: space.com

By Root

Caretaker @civilsdaily

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Dileep_Sathe
Dileep_Sathe
1 year ago

In my opinion, although the discovery of Gravitational Waves has been rewarded with the Nobel Prize in Physics in 2017, the discovery is still on a shaky footing- because it assumes the STC to be real. Actually, the real / imaginary issue is being discussed for 100 years, with no globally accepted conclusion. In fact, as a common teacher of physics (teacher of HSC physics) I have raised a conceptual difficulty in a European review journal in April 2017. Americans and Europeans are planning the new generation of detectors (See Physics Today, October 2018) but I have raised the same issue in two comments on that article, title: Future gravitational wave detectors aim to probe early universe. Our national leaders have to consider economy because Americans and Europeans also are considering economy.